U.S. Patent Application Publication No. 2012/0297828, Bailey et al., discloses a glass molding system that can be used to form 3D glass articles from 2D glass sheets in a continuous fashion. In a typical process, a 2D glass sheet is placed on a 3D mold surface and then heated to a forming temperature at one or more stations of the glass molding system. By supplying vacuum to the mold cavity through openings in the mold, the hot 2D glass sheet is conformed to the 3D mold surface to form a 3D glass article. After the conforming, the vacuum is released from the mold cavity. Process fluid is then supplied through the same mold openings to rapidly cool the 3D glass article to a temperature below the strain point of the glass. To control the mold temperature during this cooling phase, a separate line is used to supply process fluid to a cooling plate, which then operates to remove heat from the mold.
Fine adjustments to the supplied vacuum and process fluids are needed to control the accuracy of the glass shapes formed by the system. To achieve such fine adjustments, it is important to supply the vacuum and process fluids without leakage since leakage can cause process variability from one position to another in the system, which can lead to part-to-part shape variation.
The molds used in a glass molding system such as described above typically require coatings that do not react with glass at high temperatures. Since these coatings typically have a short life, it is beneficial to be able to quickly and automatically change out a mold that needs to be resurfaced.